"RainbowYOUTH believes that every person should have the right to access public bathrooms and this fear mongering from Family First is just the latest in many attempts to discredit or sensationalise issues which many of our young people struggle with."
Laura's mother also voices her opinion in the video, which lobby group Family First produced as part of a campaign to bar transgender females from using girls' and women's' facilities such as toilets and changing rooms.
"As a mother when I found out about the issue I was extremely distraught and upset," she says.
Laura's mother says the school's claims that it considered the rights of all its students before making the decision are "really incorrect".
"They have not respected the value of the girls' vulnerability. They haven't respected their thoughts on the matter. There's over 600 girls. They also have a right to have a voice.
"I think as a parent, we should've got together in the school itself before it all happened. Why didn't they ask us what we wanted to do?"
Laura adds that while she has nothing against the transgender student involved in the stoush, she takes issue with the school's lack of consideration of her views.
"[The school] never asked me my opinion. They never respected my rights. Nobody asked me first."
Whitehead, who is a trans woman, said students should be consulted but she believes most would rule in favour of transgender people being able to use the bathroom they consider most appropriate to them.
"It's straightforward. If a person identifies and presents as a female they will use the facility appropriate to them. The same goes for a male."
Whitehead said the issue was laid to rest last year and has only been rekindled by Family First.
"We are a marginalised and small community in New Zealand so we're an easy target for [Family First]. But why is this being stirred up now if it was done and dusted last year?
"Its nothing more than organised bigotry and quite frankly we're sick of it.
"All we want is to get on with our lives like everyone else."
In a video the girl, known only as Laura, says the management's decision to allow a transgender teenager, who was born male but identifies as female, to attend the all-girls' school last year shocked her.
School leadership initially told the transgender student she could use the gender-neutral toilets, but she successfully campaigned to access the girls' halfway through the school year.
Laura said it was then that she spoke to the school's management, voicing her concerns for her and other students' safety.
"And at that point I was like 'No this isn't right'," she says in the video.
"As a girl I feel uncomfortable with a guy being in the same toilets [as me]. There are already gender-neutral toilets in the school.
"Girls going through puberty and stuff, it can be quite stressful and embarrassing. And knowing that there could be a guy that could walk in, it's a little bit terrifying to think about that."
Laura says her concerns fell on deaf ears, and the principal told her if she had a problem with being in the same toilet block as the other student, she could use the unisex toilets herself.
"And that's when I thought 'hold on a minute. I'm at an all-girls' school with these girls' bathrooms and you're telling me if I don't want to use them I can go to a unisex toilet?' It doesn't make sense. It really doesn't."
